The present invention relates to an energy-saving electromagnetic switching device.
A general electromagnetic switching device usually comprises an electric relay or a contactor, which usually comprises an electromagnetic unit and a movable magnetic pole. When the electromagnetic switching device is desired to be closed, it shall be energized to produce electromagnetic force. Under the electromagnetic force, the movable magnetic pole moves downwardly to make the switching device closed. To keep the switching device in working mode, the switching device shall be kept energized continuously so that the electromagnetic force draws the movable pole to make engagement; to make the switching device disengaged, the switching device shall be de-energized so that the electromagnetic force disappears, the movable magnetic pole is restored to the original position, and thus the switching device become open. From aforementioned structure and working principle of the general electromagnetic switching device, a working electromagnetic switching device shall be continuously energized to produce electromagnetic force. Therefore, to keep switching device working, it wastes much electrical energy.
To overcome the structure disadvantage of the prior switching device, early at beginning of the 1990s, some kinds of energy-saving electromagnetic switching devices was studied. However, the early energy-saving electromagnetic switching devices usually have complicate structure and high cost of production, and seldom been merchandized on the market. Therefore, it is desired to supply an energy-saving electromagnetic switching device with much simpler structure and lower-cost than the prior switching device.